truffle-config.js

const HDWalletProvider = require('truffle-hdwallet-provider')
const fs = require("fs")
const { join } = require('path')

const mochaGasSettings = {
  reporter: 'eth-gas-reporter',
  reporterOptions: {
    currency: 'USD',
    gasPrice: 3
  }
}

// First read in the secrets.json to get our mnemonic
let secrets
let mnemonic

let filename = process.env.SECRET_FILE
if (filename == "") {
  filename = "secrets.json"
}
if(fs.existsSync(filename)) {
  secrets = JSON.parse(fs.readFileSync(filename, "utf8"))
  mnemonic = secrets.mnemonic
} else {
  console.log("No secrets.json found. If you are trying to publish EPM " +
    "this will fail. Otherwise, you can ignore this message!")
  mnemonic = ""
}

const mocha = process.env.GAS_REPORTER ? mochaGasSettings : {}


module.exports = {
  networks: {
    development: {
      host: '127.0.0.1',
      port: 7545,
      network_id: '*',
      gasPrice: 1
    },
    ganache: {
      host: '127.0.0.1',
      port: 8545,
      network_id: '*',
      gasPrice: 1
    },
    rinkeby: {
      network_id: 4,
      provider: function() {
        return new HDWalletProvider(mnemonic, 'https://rinkeby.infura.io/', 0, 10)
      },
      gasPrice: 15000000001,
      skipDryRun: true
    },
    mainnet: {
      network_id: 1,
      provider: function() {
        return new HDWalletProvider(mnemonic, 'https://mainnet.infura.io/', 0, 10)
      },
      gasPrice: 15000000001,
      skipDryRun: true
    }
  },
  mocha,
  solc: {
    optimizer: {
      enabled: true,
      runs: 200
    }
  },
    compilers : {
        solc: {
            version: "0.5.7"
        }
    }
}